Southern California -- this just in

Whitney Houston cause of death still undetermined

February 29, 2012 | 5:27
am

Authorities have not made an official determination about the cause of Whitney Houston's death and continue to actively investigate, according to law enforcement sources.

Beverly Hills police officials have said they don't believe foul play is involved, but the sources said investigators cannot pronounce a cause of death until all toxicology tests are back and detectives have concluded all interviews.

Investigators have served subpoenas on doctors and pharmacies as they try to determine whether prescription drugs played a role in her death.

Authorities collected several bottles of prescription drugs from Houston's suite at the Beverly Hilton Hotel, where she was found dead Feb. 11. But officials have said the amounts of drugs did not seem unusually large, leaving it unclear whether the medications had anything to do with the singer's death.

Houston was found in a bathtub at the hotel a day before the Grammy Awards.

The death certificate, released this month, states that the manner of death was "pending investigation."

The sources, who spoke on the condition of anonymity because the case is ongoing, said they don't know precisely when a cause of death would be determined but said it could still take another several weeks.